One more time,
thanks. I will ask such questions in another discussion lists to clarify
better..
On Wed, Oct 19, 2011 at 22:02, Bob Lantz <rlantz at cs.stanford.edu> wrote:
> Well, these questions don't seem to be Mininet questions but rather
> OpenFlow and NOX questions, which can best be answered by reading the
> OpenFlow spec, papers, and NOX documentation and/or posting to other mailing
> lists (e.g. openflow-discuss, nox-dev, etc.), but my brief replies are
> inline.
>> On Oct 19, 2011, at 3:24 PM, scolfield wrote:
>> Hi,
>> Thanks for your reply, but I have some doubt yet.
> If we don't need MAC or IP address, how we could identifier or differ one
> to another openflow switch?
>>> At the controller, switches are usually differentiated by datapath ID (or
> possibly by OpenFlow connection.)
>>> The pyswitch example can learn topology of networks?
>>> I am not aware of pyswitch having that functionality - nor does it need it.
> If I'm not mistaken, topology
> discovery in NOX is in other modules such as netapps/topology.
>> Such as a corporation architecture when
> there are hierarchical switches interconnected one to another creating
> several "layers" of switches,
> at this case, the one openflow controller connected to two distinct
> switches, can learn which ports
> to send a ping packets, for example?
>>> A ping reply is an ICMP echo reply, which is an IP packet, which can be
> routed to its destination
> by whatever means you choose. It would probably be reasonable to originate
> it from the switch
> it came into (and probably the ingress port) rather than some random port
> on another switch.
>> The packet in messages will be forwarded automatically through
> switches until reach a controller?
>>> PACKET_IN messages are OpenFlow messages which are sent from switch to
> controller.
>>> --
> scolfield
>>> On Wed, Oct 19, 2011 at 17:54, Bob Lantz <rlantz at cs.stanford.edu> wrote:
>>> p.p.s. Step 1 may not be necessary if the packets "to the switch" won't
>> match any other rules and will be forwarded to the controller by default.
>>>> On Oct 19, 2011, at 12:52 PM, Bob Lantz wrote:
>>>> If you want to use OpenFlow, then using the Linux networking stack to
>> assign a MAC or IP address to a switch port is unnecessary and undesirable.
>>>> To "assign" a MAC or IP address to the switch,
>>>> 1. Use OpenFlow to install a rule to forward packets to whatever "switch"
>> MAC or IP address you like to the controller.
>>>> 2. When you want the "switch" to send packets, simply create them with
>> whatever source MAC and source IP you like.
>>>> To summarize: this is an important design aspect of OpenFlow which needs
>> to be understood.
>>>> Bob
>>>> p.s. To perhaps clarify this issue, I think we may wish to change Mininet
>> to raise an error if you attempt to assign an IP or MAC address to a switch.
>>>> On Oct 19, 2011, at 9:36 AM, scolfield wrote:
>>>> Hi,
>>>> I created a python script to configure one topology network...
>> and why can I set the mac address that I need?? For example,
>> such as:
>>>> *sw = net.addSwitch( 'switch', ip='10.0.1.1', mac='01:36:42:00:00:01')*
>>>> I'm using Mininet class for this purpose... anybody have any idea, what is
>> wrong?
>> That mac address that I want to set, don't set correctly,..
>> set another mac address every time..
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